1. Field of the Invention
This invention relates to a branching section of a sheathed multicore optical fiber to be realized by an improved branching mechanism.
2. Description of the Related Art
When a sheathed multicore optical fiber is branched, typically a series of operations as described below by referring to FIG. 5(A) through 5(C) of the accompanying drawings are carried out.
Referring firstly to FIG. 5(A), a cylindrical boot 2a having a tapered section and a cylindrical holding member 3a are fitted onto an end portion of a sheathed multicore optical fiber 1 comprising a plurality of strip-shaped optical cords to cover the outer peripheral surface of the sheath 4 at that portion.
Then, the sheath 4 of the multicore optical fiber 1 is partly removed at a very end portion extending from the holding member 3a to expose corresponding end portions of the optical fiber cores 5 and tension-resistive fibrous members 6 it comprises.
Then, a cylindrical sleeve 7 is fitted to the unsheathed end portion of the optical fiber 1 to partly cover the exposed optical fiber cores 5 and, subsequently, tubes 9 each having tension-resistive members 8 are put on the respective remaining end portions of the optical fiber cores 5. Thereafter, a cylindrical holding member 3b and a cylindrical boot 2b having a tapered section is fitted onto the tubes 9 to partly cover the tubes 9.
Then, as shown in FIG. 5(B), the corresponding remaining end portions of the tension-resistive members 6, 8 are placed on the outer peripheral surface of the sleeve 7 at the opposite ends and the holding members 3a, 3b and the boots 2a, 2b are sequentially moved onto the sleeve 7 and securely held there to establish a complete branching section 10 as illustrated in FIG. 5(C).
The end portions of the optical fiber cores 5 of a branching section 10 which is prepared in this manner are protected by a sleeve 7 and respective tubes 9 and made resistive against tension by the sleeve 7 and the end portions of the tension-resistive members 6, 8 secured to the sleeve at the opposite ends thereof so that the branching section 10 is consequently highly resistive against tension.
However, since each of the components of a branching section 10 as illustrated in FIG. 5(C) have a circular cross section, the optical fiber cores 5 in the sleeve 7 can be inevitably twisted and/or bent to damage their transmission capabilities when the components are assembled.
While it is highly desirable to check the established branching section 10, the optical fiber cores 5 in the sleeve 7 are invisible from outside and any twisted and/or bent optical fiber cores 5 are normally left unchecked.
If the sleeve 7 is made of a transparent material and twisted and/or bent optical fiber cores 5 are visible from outside, any efforts of remedying such faulty optical fiber cores 5 can significantly reduce the efficiency of branching operation.